Treatment of iron ores, &amp;c.



No. 803,886. PATBNTED Nov. 7, 1905.

- c. ELLIS.

TREATMENT 0F IRONORES, zo.

APPLIOATION FILED JUNE 5,1905.

WITNESSES: y

OARLETON ELLIS, OF NEW YORK, N. Y.

TREATMENT OF IRON CRES; 81.6.

Specification o1" Letters Patent.

PatentedNov. '7, 1905.

Application lle June 5,1905. Serial No. 263,889.

To all why/2771, if 711,111.7/ concern:

-and State of New York. have invented certain new and useful Improvements in Treatment of Iron Ores, &c.. of which the following is a specification.

This invention relates to process for the manufacture of metallic iron which dispenses with the cupola or blast furnace.

There are many ores of iron which cannot be economically or satisfactorily reduced in the cupola-furnace; and the present process has for its object the manufacture of iron or steel, preferably in a continuous manner, by the employment of a. combination of liames which have sufficient reducing action to elfect the reduction of the oxid of iron to the metallic state and which at the same time have sufficient heat intensity to afford an output of commercial significance.

It has been proposed to manufacture iron byy feeding the ore through a rotary kiln somewhat resembling those used in the manufacture of cement and to apply to the ore a reducing flame produced from pulverized fuel. Inasmuch as it is necessary in order to secure a complete reduction to have the liame of high temperature and at the same time of a reducing' nature, (two properties which are incompatible,) it has not been possible to successfully manufacture iron in this manner. Ordinarily only tenv to fifteen per cent. of the ore is reduced, and being mingled with so large an amount of inert matter the separation of the metal from the dross is practically impossible.

In carrying out the present process .rotary kilns may also be employed; but the ame application is made such that the high temperature required is accompanied by a powerful reducing action which permits of the practically complete reduction of the ore. This is accomplished by the employment of two or more tiames or flame strata, one portion. that coming in contact with the ore, containing an excess of combustible matter-such, for instance, as carbon monoXid-and therefore having marked reducing properties, while another portion of the flame, more remote from the ore mass, is maintained at a high temperature due tothe presence of plenty of oxygen or air.

By reference to the accompanying diagrammatic drawing it will be evident in what manner this process may be carried out.

In the drawing, 1 is a rotary kiln or barrel having a thick lining of refractor \v material and mounted on rollers. It is rotated by the mechanism 2. In its upper part is a chamber or housing 3, supporting the stack 4, and through which projects into the upper part of the kiln the feeding-spout 5. In the lower part of the housing is the cleaning-door 6. The stack 4 is supplied with a damper 7.

8' is a feed-hopper from which by means of a conveyer 9 the ore is delivered to the spout 5 and falls to the lower part of the kiln-barrel. The lower end of the kiln isclosed by the header 10, which is supported ou the truck l1. ln the kiln are the openings or ports 12, 13, and 14. The port 12 has connection' with the pipe or conduit 15, through which fresh air is supplied by the fan 16. Interposed in this conduit is shown a heatingstove 17. This conduit 15 is equipped with the damper 18.

19 is a vertical passage having connection with the ports 13 and 14. This passage communicates with the iiues 20 and 2l, through which a su pply of gas is passed from the gasproducer 22, the "down-comer 23 of said gas-producer having connection with the horizontal underground lue 21.

24 is a damper in the down -comer,7 equipped, as usual, with a sand seal.

In the upper part of the producer are hoppers for the introduction of the fuel. In the lower part is shown a water seal 26, a blastbale 27, and twyers 28 for the admission of the air-blast. Connected with the twyers is the conduit 29, which enters the stack 4. Interposed in this conduit is the fan 30. On the inlet side of the fan is an air-opening 31. The valves or dampers 32 and 33 regulate the flow, respectively, of the products of combustion drawn from the stack 4 and of the air admitted through the opening 31. In the conduit 29 is also located a steam-jet 34. At the discharge end of the kiln underneath the header is shown the conveyer-trough 35.

My method of operation is as follows: Iron ore mingled, if desired, with any suitable iiuX or with carbonaceous material is fed from the hopper 8 into the kiln in its upper part, and as the kiln rotates the material moves gradually toward the lower end. Through the port 12 a supply of air, preferably highly heated, is admitted to the kiln and through the ports 13 and IUC IIO

14 a stream of combustible gas. That issuing from the port 13 mingles with the air from the port 12, and a Hame of very high temperature is produced, which heats up the thick walls of the kiln-barrel and by virtue of its heat-radiating qualities reverberates an intense heat upon the mass of ore in the bottom of the kiln. Through the port 14 only producer-gas issues, and owing to its high content of carbon monoxid the atmosphere around the material is of a strongly-red ucing nature. B v virtue of thel heat radiation from the iiame above and from thel kiln-lining and b v heat conducted from the kiln-lining to the material by contact as the kiln revolves, in conjunction with the red ucing action above mentioned, the ore is rapidly deprived of its oxygen, and the iron therein contained is thereby rapidly and completely converted to the metallic state, whereupon the ore discharges into the conveyer and is taken to any desired point for further treatment. It is desirable to have the gas which enters at 14 of such a temperature that its gravity is greater than the air entering the port 12, thereby preventing the too rapid mingling of these two currents. In that way the reducing-current will travel a long distance into the kiln before it mixes with sufficient air to exert an oxidizing action, and by that time it will ordinarily have reached the upper portion of the kiln. By its combustion at this point heat is evolved, which assists in bringing the raw ore to the temperature necessary to effect the pro per reduction in the lower portion of the kiln.

The air supplied through port l2 may be heated in any suitable manner. For instance, a continuous regenerator may be placed in the stack or housing, or the products of combustion may be drawn from the housing and passed through a reversing-regenerator or continuous recuperator, as desired. Another method of prehcating the air, which is not as efficient as those above mentioned, is that of' placing tubes or passages alongside the gasflues and in thereby transferring a portion of the heat of the gas to the entering air. In this case it is, however, difficult to bring the air to such a temperature that the proper stratification of the dame-currents is secured.

It is obvious that otherfuels than producergas may be usedHas, forinstance, water-gas, natural gas, oil, or pulverized coal or combinations of these. For instance, the flame from the upper part of' the header may be developed by powdered coal, while that from the lower part of the header may be developed by the use of oil or producer-gas.

The operation of the gas-producer by products of combustion requires the proper proportioning of carbon dioxid and oxygen to secure a temperature at which the coal does not fuse or clinker in the producer. Asteamjet has also been shown, as it is sometimes desoassc sirable to operate with steam or air or with steam, air, and products of combustion, depending to some extent on they nature of the ore.

It will be evident that any method involving the use of asinglejet of iiame isincapable of giving' simultaneously the desired heating` and reducing action. To produce a flame of a reducing character, insufcient oxygen for combustion should be supplied. This results in a fiame of low temperature, which cannot impart heat with sufficient rapidity to the ore mass to bring about rapid and complete reduction. Consequently with a single flame it has been found by experiment that a very small output of only partially-reduced ore is obtained. The present process involving, as it does, the use of' two or more flames so located with reference to the ore that the re- `ducing-fiame or reducing-current is between v sists in treating a progressively-advancingy stream of the ore with aflame of high heat intensity and in interposing between said flame and ore a fiame or current of' a reducing char acter.

2. Process for manufacturing metallic iron which consists in treating a nrogressively-ad vancing stream of finely-divided ore with a high-temperature flame, and in interposing between said high-temperature flame a stratum of a reducing-gas.

3. Process for manufacturing metallic iron which consists in treatingaprogressively-ad- Vancing stream of finely-divided ore with a high-temperature flame, and in interposing between said high-temperature Hanne a stratum of producer-gas.

4. Process for manufacturing' metallic iron which consists in subjecting' an ore of iron to a ame of high heat intensity and in interposing between said fiame and ore a flame or current of a reducing character.

5. Process for manufacturing iron which consists in subjectingl an ore of iron in combination with a flux to a Hanne of high heat intensity and in interposing between said flame and ore a flame or current of a reducing character.

Signed at New York city, in the county of New York and State of New York, this 17th day of May, A. D. 1905.

CARLETON ELLIS.

Witnesses:

CHAs. E. BROWN, ARTHUR E. WHITE. 

